Grouping of logical or physical assets that share common security requirements.
- NOTE: All unqualified uses of the word “zone” in this standard should be assumed to refer to a security zone.
- NOTE: A zone has a clear border with other zones. The security policy of a zone is typically enforced by a combination of mechanisms both at the zone edge and within the zone. Zones can be hierarchical in the sense that they can be comprised of a collection of subzones
.Source: ANSI/ISA–99.00.01–2007, Security for Industrial Automation and Control Systems, Part 1: Terminology, Concepts, and Models, 29 October 2007. National Standard